题目内容
Vitamin D helps bones and muscles grow strong and healthy．Low levels of vitamin D can lead to diseases such as rickets(软骨病), mainly found in children．The thinning of bone is a common problem as people, especially women, get older．
But more and more research is suggesting that vitamin D might also help prevent many diseases．The easiest way to get vitamin D is from sunlight．The sun’s ultraviolet(紫外线的)rays react with skin cells to produce vitamin D．But many people worry about getting skin cancer and skin damage from the sun．As a result they stay out of the sun．Also, darker-skinned people produce less vitamin D than lighter-skinned people．The amount also de-creases in older people and those living in northern areas that get less sunlight．
Not many foods naturally contain vitamin D．Foods high in this vitamin include oily fish and fish liver oils．Farmed fish have only about one-fourth as much vitamin D as wild fish．Small amounts of vitamin D are found in beef liver, cheese and egg yolks．But most of the vitamin D in the American diet comes from foods such as milk．
Research in the last several years has shown that low levels of vitamin D may increase the risk of heart attacks in men and deaths from some cancers．More doctors are now having their patients tested for their vitamin D levels．But as research continues, some experts worry that if people take too much vitamin D, it might act as a poison, Also, skin doctors warn people be careful with sun exposures because of the risk of skin cancer．
1.The first paragraph is mainly about ．
A．the muscle diseases B．the sources of vitamins
C．the importance of health D．the functions of vitamin D
2.Which of the following people produce the least amount of vitamin D?
A．Elderly darker-skinned people．
B．Young lighter-skinned people．
C．Elderly lighter-skinned people．
D．Young darker-skinned people．
3.People can get the most vitamin D from ．
A．beef liver B．cheese C．wild fish D．farmed fish
4.What can we infer from the text?
A．Being exposed to sunlight is the safest way to get vitamin D
B．Lack of vitamin D can make people age quickly
C．Proper vitamin D levels people need are still not determined now．
D．The vitamin D level is higher in men than in women．
1.D
2.A
3.C
4.C
名校课堂系列答案A healthy amount of sunshine may be the secret to staying young. British scientists have discovered.
Vitamin D is produced naturally by the skin in response to(对…的反应) sunlight and may help to slow the ageing process and protect against heart disease, according to the study.
Researchers from King’s College London studied 2,160 women aged between 18 and 79, looking at their telomeres--- a biological marker of ageing found in DNA. As people get older, their telomeres get shorter and they become more susceptible(易受伤害的) to certain illnesses.
But the study found women with high levels of vitamin D had comparatively longer telomeres--- a sign of being biologically younger and healthier.
The study suggests vitamin D may help to slow down the ageing process of DNA, and therefore the ageing process as a whole.
Lead researcher Dr Brent Richards said, “These results are exciting because they show for the first time that people who have higher levels of vitamin D may age more slowly than people with lower levels of vitamin D.” This could help to explain how vitamin D has a protective effect on many ageing related diseases, such as heart disease and cancer.”
Professor Tim Spector, a co-author of the report, added, “Although it might sound absurd
(荒唐的), it’s possible that the same sunshine which may increase our risk of skin cancer may also have a healthy effect on the general ageing process.”
Vitamin D made by the action of sunlight on the skin accounts for 90 percent of the body’s supply, but lower levels can also be got through food such as fish, eggs and breakfast cereals(粥).
Other studies have suggested the vitamin plays a key role in protecting against cancer and heart disease.
【小题1】 A certain amount of sunshine helps people stay young because _____.
| A．people feel happy and energetic in the sun |
| B．sunshine protects people against heart disease |
| C．vitamin D makes one’s skin look young and healthy |
| D．vitamin D may help to slow the ageing process |
| A．sunlight causes skin cancer to people with high level of vitamin D |
| B．the study generally has a healthy effect on the general ageing process |
| C．vitamin D can only be got from fish, eggs and breakfast cereals |
| D．the higher levels of vitamin D people have, the more slowly people may age |
A. Telomeres are important signs of ageing of the DNA.
B. Sunlight can be dangerous as it causes skin cancer.
C. Sunlight does a great deal of good to our health.
D. Vitamin D can also be gained from food.
【小题4】 What is the best title of the passage?
| A．Secret of Staying Young |
| B．Vitamin D Helps Slow Ageing |
| C．Sunlight and Vitamin D |
| D．Sunlight and Health |
Below is some advice on how to prevent cancer:
8 Ways to Avoid Cancer in Your Life
1. Eat Blueberries
Aside from being a healthy and delicious snack, blueberries contain pterostilbene, which has important colon（结肠） cancer-fighting prosperities. But wait, it gets better. Blueberries also offer a large dose of vitamins C (14 milligrams per cup). So at breakfast, try to take in a cup and a half of blueberries in your cereal or yogurt, or mixed with other berries.
2. Drink Pomegranate（石榴）Juice
The deep red juice of the pomegranate contains polyphenols, isoflavones and ellagic acid, which together create a powerful anticancer mixture. Most recently, researchers from the University of Wisconsin at Madison has discovered that 16 ounces of pomegranate juice per day also may inhibit the growth of lung cancer.
3. Relax
Feeling stressed or worried? Find ways to relax and you may reduce your chances of developing cancer. Purdue University researchers tracked 1,600 men over 12 years and found that half of those with high levels of worry died during the study period. Only 20 percent of the optimists died before the study were completed, while 34 percent of the extremely anxious men died of some type of cancer. Instead of stressing about the past or future, focus on the present and relax!
4. Take Selenium（硒）
Selenium is well known for its cancer-fighting properties. In a study of almost 1,000 men, researchers from the Journal of the National Cancer Institute found that when men with the lowest initial levels of selenium in their bodies received a daily supplement over a 4 year period, they cut their prostate（前列腺） cancer risk by a remarkable 92 percent. However, it is possible to get too much of a good thing, so monitor your intake of selenium-containing supplements, Brazil nuts, tuna, meats and grains carefully.
5. Eat Sushi（寿司）
Seaweed may not be your idea of a great snack, but it is high in fiber, calcium and iron, and dry, roasted seaweed sheets used in sushi provide the additional benefits of vitamins A and C. Sushi rolls are also high in protein— a typical spicy tuna roll has only 290 calories but packs 24 grams of protein. So don’t skimp（节省）on the Sushi!
6. Enjoy the Outdoors
Vitamin D causes early death of cancer cells. A study published in the American Journey of Clinical Nutrition reported that women who supplemented their diets with 1,000 international. Units of vitamin D every day had a 60 percent to 77 percent lower incidence of cancer ever a four-year period that did women taking a placebo(无效对照剂). Experts recommend supplementing your fun in the sun with 1,100 to 2,000IU of vitamin D each day.
7. Breathe Clean Air
There’s no question that secondhand smoke kills. A recent American Journal of Public Health study showed that nonsmokers working in smoky places had three times the amount of carcinogen（致癌物质） in their urine（尿） than nonsmokers working in smoke-free locations. What’s worse, their levels of the carcinogen rose 6 percent for every hour worked. Nine states have banned smoking in all workplaces, bars and restaurants. The message is clear: Do whatever you can to avoid the cloud of smoke.
8. Break a Sweat
Even a small amount of exercise can offer major cancer-fighting benefits. In a study of 29,110 men published in the International Journal of Cancer, men who exercised just once a week had a percent lower risk of metastasis(转移性) prostate cancer than men who didn’t work out at all. The better the frequency, duration and intensity of the exercise, the bigger the reduction in risk, according to the study.
【小题1】To prevent yourself from catching colon cancer, you should eat ____ as often as possible.
| A．sushi | B．blueberries | C．pomegranates | D．Vitamin D |
| A．he is very fond of exercise every day. |
| B．he is addicted to smoking |
| C．he is always feeling extremely stressed or worried |
| D．he likes to have meals in restaurants |
| A．Having a daily supplement of selenium |
| B．Drinking a cup of pomegranate juice every day |
| C．Breathing fresh air now and then |
| D．Taking exercise at least once a week |
| A．have a daily supplement of vitamins B and C |
| B．try to ignore the secondhand smoking |
| C．take in as many selenium-containing supplements as possible |
| D．having exercise as often as possible |